Before operations, the skin or mucous membrane in the region of the operation area is treated with antiseptic disinfectants. Here, it is necessary to ensure complete wetting of the epithelium in order to guarantee complete disinfection. For this reason, intensely coloured preparations which permit visual monitoring of the application of the disinfectant are usually used for disinfecting the skin and mucous membrane.
However, the disadvantage of these compositions is that colour changes of the skin which may occur during the operation, such as, for example, pallor as a result of depletion of blood or a blue colour due to inadequate oxygen saturation of the blood, for example in cardiac insufficiency or pulmonary diseases, are masked by the dye, and any necessary measures on the part of the surgeon are thus delayed or even completely prevented. In addition, the pronounced adhesion of the dyes to the skin, in particular of patients, is found to be very troublesome. Moreover, clothing, operating tables, floors, equipment, etc. soiled by the dyes used are difficult to clean.